1. Field of the Invention
The subject invention relates to label printers. More particularly it relates to label printers for printing labels containing information which varies from label to label in real time (i.e. for immediate use as the varying information is determined).
It is well known to provide labels which are fixed to a continuous web of release liner. Such labels are fixed to the release liner in a regular pattern by an adhesive which does not cure when in contact with the release liner but remains tacky so that the labels may be removed from the liner and affixed to another object. A typical use for such labels would be as address labels. A web of blank labels could be printed with addresses from a mailing list on the line printer of a computer system then removed from the release liner and affixed to envelopes.
Known information may be pre-printed on such labels using conventional printing technology (e.g. "FRAGILE" or "URGENT" stickers). As noted above information which varies from label to label may be printed as computer output. However, neither of these approaches has proven completely satisfactory for applications which require that labels be printed in real time. For example, in manifest systems used by parcel shippers to determine the shipping costs and generate manifests for items to be shipped it is frequently desirable to provide address labels which include both fixed information, such as the identity of the shipper and variable information which can only be determined at the time the label is printed. Thus, in manifest systems the shippping cost cannot be determined until the parcel is weighed by the manifest system and the label must be printed in real time.
A system for real time label printing is disclosed in reissue patent Re 30,749; for "Label Printing and Applying Apparatus"; to Paul H. Hamisch, Jr.; reissued Sept. 29, 1981. This patent discloses a system for generating unit price labels for use in supermarkets and the like. Also, a computer driven label printer is marketed by the Swedot Corporation of Sweden as its model number 8222.
Though the above described systems do provide real time label printing and separation of printed labels from the release liner they have limited printing capability. Thus when the Sweda system is used in a manifest system it is necessary to pre-print the fixed information on the labels since the Sweda printer is not capable of printing all the necessary information on the labels.
Heretofore computer output line printers have not been used to print labels in real time, though they are capable of printing the full range of necessary information on such labels, because they have lacked the capability to separate labels from the release liner. Without this capability it is necessary for the operator to remove the label by hand; a process which greatly reduces productivity. In the past where labels have been printed by computer it has been found most efficient to provide a separate system for separating the labels from the release liner. Such systems are marketed by the Dispensa-matic division of Commercial Mailing Accessories, Inc. of St. Louis, Mo. In the Dispensa-matic systems, as in most, if not all systems with label separating capability, the labels are separated from the release liner by drawing the web cross a separating edge which introduces an angle into the web path. Because the labels are relatively stiff in comparison to the release liner and the adhesive fixing the labels to the release liner is not cured the angle in the web path causes the labels to peel or separate from the release liner. While analytical determination of the necessary angle is a complex process, involving the stiffness of the labels, the adhesive force between the label and the release liner, the radius of the separating edge, and the force applied to the draw the web over the separating edge, in practice those familier with the label separating art have been readily able to determine appropriate angles through a simple process of trial and error.
Accordingly it is an object of the subject invention to provide a system for printing and dispensing shipping labels, and the like, in real time.
It is a further object of the subject invention to provide a system for printing mailing labels, and the like, containing both fixed and variable information in an efficient manner.
It is a still further object of the subject invention to provide a system for printing mailing labels, and the like, wherein the above objects may be achieved at a low incremental cost.